Electron gun assembly and cathode ray tube with the same

Abstract

An electron gun assembly for a cathode ray tube where the distortion of the electron beam that ordinarily occurs at the periphery of the screen is reduced. The electron gun assembly includes a cathode for emitting electrons, and a plurality of grid electrodes having a control electrode facing the cathode. The grid electrodes sequentially follow the cathode to focus and accelerate the electrons emitted from the cathode. The control electrode has a beam passage hole with a horizontal length H, and a vertical length V being larger than the horizontal length H. The ratio of the vertical to horizontal lengths satisfies the following condition: 1.03≦V/H≦1.63.

1. An electron gun assembly, comprising:
 a cathode adapted to emit electrons; and 
 a plurality of grid electrodes that includes a control electrode that is arranged to face the cathode, the grid electrodes sequentially following the cathode and being adapted to focus and accelerate the electrons emitted from the cathode, the control electrode being perforated by a beam passage hole having a horizontal length H and a vertical length V, the ratio of V/H satisfying the inequality 1.03≦V/H≦1.63. 
 
   
   
     2. The electron gun assembly of  claim 1 , the beam passage hole being of a shape selected from the group consisting of an oval, a track and a rectangle. 
   
   
     3. The electron gun assembly of  claim 1 , each of the grid electrodes, except for the control electrode, being either perforated a circular beam passage hole or having a columnar body adapted to internally allow a passage of the electron beam. 
   
   
     4. The electron gun assembly of  claim 1 , the cathode being an only cathode for emitting a stream of electrons in the electron gun assembly. 
   
   
     5. The electron gun assembly of  claim 1 , the plurality of grid electrodes comprises:
 the control electrode; 
 an accelerating electrode; 
 a first anode electrode; 
 a focusing electrode; and 
 a second anode electrode, the first anode electrode and the second anode electrode being electrically connected to each other. 
 
   
   
     6. The electron gun assembly of  claim 5 , the second anode electrode partially surrounding the focusing electrode, the focusing electrode comprising a diameter-enlarged portion arranged within the second anode electrode. 
   
   
     7. A cathode ray tube, comprising:
 an electron gun assembly that includes a cathode, a plurality of grid electrodes that includes a control electrode arranged to face the cathode, the grid electrodes sequentially following the cathode and being adapted to focus and accelerate an electron beam emanating from the cathode, and a support adapted to serially arrange and support the grid electrodes; 
 a neck internally mounted with the electron gun assembly; 
 a funnel and a panel arranged to a front of the neck; 
 a deflection yoke arranged around an outer circumference of the funnel and adapted to produce a magnetic field that deflects the electron beam; and 
 a phosphor screen arranged on the inner surface of the panel, the control electrode being perforated by a beam passage hole arranged with a horizontal length H and a vertical length V, a ratio of V/H satisfying the inequality 1.03≦V/H≦1.63. 
 
   
   
     8. The cathode ray tube of  claim 7 , the electron gun including only one cathode, the phosphor screen being a color selected from the group consisting of red, green and blue. 
   
   
     9. The cathode ray tube of  claim 7 , an inner surface of the panel comprising a convex surface arranged to face the neck. 
   
   
     10. The cathode ray tube of  claim 7 , the beam passage hole of the control electrode being of a shape selected from the group consisting of an oval, a track and a rectangle. 
   
   
     11. The cathode ray tube of  claim 7 , the grid electrodes comprises:
 the control electrode; 
 an accelerating electrode; 
 a first anode electrode; 
 a focusing electrode; and 
 a second anode electrode, the first anode electrode and the second anode electrode being electrically connected to each other. 
 
   
   
     12. The cathode ray tube of  claim 11 , the second anode electrode partially surrounding the focusing electrode, the focusing electrode comprising a diameter-enlarged portion arranged within the second anode electrode.